The Storm Pedal probably originated in the old
Drum Pedal and the German
Hummel. As made by Cavaillé-Coll
it was a pedal which, on depression, drew down successively six or seven
notes from the bottom of the pedal board upwards. The effet, as may well
be imagined, is realistic -- particularly when the 32 ft. reed is drawn.
As Mr. Robertson remarks, the contrivance is rather superfluous, since
a really imposing effect can be got by sitting on the keys!
Manchester Town Hall; Sheffield Albert Hall; Carmelite Church,
Kensington (formerly), (all by Cavaillé-Coll); Seville
Cathedral (Qauilino Amézua, 1903).

Sumner lists Donner as simply “a thunder effect in German organs,
made by playing some of the large bass pipes together”.

Examples

Osiris contains eight examples of Orage, seven example of
Effet[s] d'Orage, two examples each of Donner and Tonnerre,
and one example each of Thunder Pedal and Storm Pedal.